Integral image elements which use a lenticular lens sheet or a fly's eye lens sheet, and a three-dimensional integral image aligned with the sheet, so that a user can view the three-dimensional image without any special glasses or other equipment, are known. Such imaging elements and their construction, are described in "Three-Dimensional Imaging Techniques" by Takanori Okoshi, Academic Press, Inc., New York, 1976. Integral image elements having a lenticular lens sheet (that is, a sheet with a plurality of adjacent, parallel, elongated, and partially cylindrical lenses) are also described in the following Unites States patents: U.S. Pat. No. 5,391,254; U.S. 5,424,533; U.S. 5,241,608; U.S. 5,455,689; U.S. 5,276,478; U.S. 5,391,254; U.S. 5,424,533 and others; as well as allowed U.S. patent application Ser. No. 07/931,744. Integral image elements with lenticular lens sheets use interlaced vertical image slices which, in the case of a three-dimensional integral image, are aligned with the lenticules so that a three-dimensional image is viewable when the lenticules are vertically oriented with respect to a viewer's eyes. Similar integral image elements, such as described in U.S. Pat. No. 3,268,238 and U.S. 3,538,632, can be used to convey a number of individual two-dimensional scenes (such as unrelated scenes or a sequence of scenes depicting motion) rather than one or more three-dimensional images.
Integral image elements using reflective layers behind the integral image to enhance viewing of the integral image by reflected light, are also described in U.S. Pat. No. 3,751,258, U.S. 2,500,511, U.S. 2,039,648, U.S. 1,918,705 and GB 492,186.
Previous lenticular imaging methods typically used a method for exposing the images through the lenticular material. This causes flair because multiple views must be exposed and each view introduces a background flair into the overall scene due to light scatter from the lenticular material. Resolution is also lost because the lenticular material does not have as high an optical resolution as is necessary for high quality imaging and as a consequence resolution is lost during the exposure of the image.
A technique for exposing a light sensitive layer on the flat back side of a lenticular sheet, has been previously described in U.S. Pat. No. 5,276,478. One difficulty with exposing from behind in this manner is that some light will pass through the light sensitive layer and be reflected back at an angle from the front surface of the lens sheet, to expose additional areas of the light sensitive layer. This effect, known as halation, results in a loss of sharpness in the recorded image. The possibility of using an antihalation layer between the sheet and recording layer is mentioned in U.S. Pat. No. 5,276,478. However, the light source described is a point source of light (such as a laser, LED or CRT) which is scanned over the recording layer from the back side to form the image. This necessarily requires a relatively complex scanning mechanism with its associated circuitry and mechanical parts.
It would be desirable then, to provide a method of obtaining an integral image element by exposing a light sensitive layer on the back side of an integral lens sheet from behind the light sensitive layer by a means which does not require scanning a spot source of light. Such a method should also result in low flair and high resolution, as well as low halation.